Radio-frequency (RF) powered implantable stimulators and battery powered implantable stimulators are described in the art. See, for instance, U.S. Pat. Nos. 5,193,539 (“Implantable Microstimulator); U.S. Pat. No. 5,193,540 (“Structure and Method of Manufacture of an Implantable Microstimulator”); U.S. Pat. No. 5,312,439 (“Implantable Device Having an Electrolytic Storage Electrode”); U.S. Pat. No. 6,185,452 (“Battery-Powered Patient Implantable Device”); 6,164,284 and 6,208,894 (both titled “System of Implantable Device for Monitoring and/or Affecting Body Parameters”). Each of these patents is incorporated herein by reference in its respective entirety.
Implantable stimulators configured to prevent or treat various disorders associated with prolonged inactivity, confinement or immobilization of one or more muscles are taught, e.g., in U.S. Pat. Nos. 6,061,596 (“Method for Conditioning Pelvis Musculature Using an Implanted Microstimulator”); U.S. Pat. No. 6,051,017 (“Implantable Microstimulator and Systems Employing the Same”); 6,175,764 (“Implantable Microstimulator System for Producing Repeatable Patterns of Electrical Stimulation”); 6,181,965 (“Implantable Microstimulator System for Prevention of Disorders”); 6,185,455 (“Methods of Reducing the Incidence of Medical Complications Using Implantable Microstimulators”); and 6,214,032 (“System for Implanting a Microstimulator”). Each of these patents is incorporated herein by reference in its respective entirety.
A typical implantable stimulator is intended to permanently remain in the body of a patient once it is implanted. Hence, transcutaneous communication between an implantable stimulator and an external device may be important for the stimulator to function properly. For example, communication with the implantable stimulator may be effected to perform a number of functions including, but not limited to, transferring power to the stimulator, transferring data to and from the stimulator, programming the stimulator, and monitoring the stimulator's various functions.